The mess you've just created will come off fairly easy using a non-metallic hard-bristled brush.
Now comes the fun part! Take the orbital Sander (or if you're new and/or inexperienced) please use the Palm Sander with a 100-150 grit and start the excrutiatingly tedious process of smoothing down the aluminum. Using the Palm Sander will be slower, but safer. Here, I use the random orbital air sander.
As you see, using the Orbital Sander remove a lot of stock material, but leaves swirls and lots of em! These swirls were produced with a 120 grit orbital sanding disk.
If you DID use an orbital sander even after being warned, then start to panic because you've already f*cked up! I should kick you out of class right now! But wait...because you've left some unsightly and deep swirl marks, we'll move onto the Palm Sander to help smooth things out.
With the Palm Sander, you'll have to go through MANY different grits in order to attain a smooth finish! I go from 150 grit all the way to 600 grit on the sander. At 600 grit, the frame should be smooooooooooth!
